Scattering of He Atoms from Crystal Surfaces: A Tentative Analysis on the Surface Crystallography of LiF(001)

Abstract

This Letter describes a theoretical treatment of the excellent experimental results of Boato, Cantini, and Mattera for the He-LiF(001) system, in terms of a hard corrugated model for the surface. From the agreement achieved between theory and experiments, I conclude that one can represent the corrugated surface by ${z}_{1}(x,y)=\frac{1}{2}{\ensuremath{\zeta}}_{1}[cos(\frac{2\ensuremath{\pi}x}{a})+cos(\frac{2\ensuremath{\pi}y}{a})]+\frac{1}{2}{\ensuremath{\zeta}}_{2}{cos[\frac{2\ensuremath{\pi}(x+y)}{a}]+cos[\frac{2\ensuremath{\pi}(x\ensuremath{-}y)}{a}]}$, with ${\ensuremath{\zeta}}_{1}=0.307\ifmmode\pm\else\textpm\fi{}0.003$ \AA{} and ${\ensuremath{\zeta}}_{2}=0.017\ifmmode\pm\else\textpm\fi{}0.003$ \AA{}. This implies that the ${\mathrm{Li}}^{+}$ appear to be displaced upwards from the crystal surface by 0.036\ifmmode\pm\else\textpm\fi{}0.006 \AA{}.